For producing radiographs, amplifying foils are known which convert the incident X-ray radiation into a radiation falling in the range of visible light. In general, these amplifying foils used to be arranged before and behind the film to be shot. In this case blackening of the film is primarily caused by the radiation falling into the visible range. Application of amplifying foils enables reduction of exposure time, however, it is accompanied by a loss in the sharpness of the image.
From the PCT Application PCT/HU83/00062 published under the number WO 84/02399 a method for producing radiographs is known, in which a modifying body of laminar structure is placed between the object to be examined and the film. The modifying body consists of thin Pb layers arranged on one another, which are applied onto a carrier sheet. If in the object examined material thickness corresponding to different ray paths is changing, e.g. the object is a pipe, the modifying body automatically acts as a compensator. In such a manner, on the image thus obtained far more details of the object can be seen and evaluated, however, the exposure times have to be increased.
In radiologic practice materials of the films used for preparing radiographs respond only to an X-ray or gamma radiation, the energy of which surpasses a given limit of energy level. In general, sensitivity is the highest immediately above said energy level, thereafter with increasing energy it drops considerably. Just in order to eliminate this dependency on energy, sensitivity of usual films used to be modified by means of filters so as to achieve nearly equal sensitivity in a broader range of energy. This, however, involves a poor sensitivity of the film in the whole energy range, requiring an increased radiation intensity or a longer exposure time in preparing radiographs.